Liquid crystal display made of thin film transistors has characteristics such as small size, low power consumption, no radiation, and so on, thus dominates the current flat panel display market. Liquid crystal panel is an important component of the liquid crystal display, and comprises an array substrate, a color filter substrate, and a liquid crystal layer filled between the array substrate and the color filter substrate.
The array substrate comprises a plurality of thin film transistors arranged in an array, which are formed on a glass or plastic substrate by sputtering chemical vapor deposition and other processes. The gate electrodes of the thin film transistors in the same row are connected together by a gate line, and the source electrodes of the thin film transistors in the same column are connected together by a data line, wherein the materials of the gate line and the data line are typically tantalum, chromium, molybdenum, or an alloy of at least two of them.
With the gradually increasing size of the liquid crystal display, the lengths of the gate line and the data line in the array substrate also increase, resulting in increasing resistance of the gate line and the data line. Since the signal delay time of a signal line is proportional to the resistance of the signal line, an increase in the resistance of a signal line will result in an increase in the signal delay time of the signal line. When the signal delay time reaches to a certain extent, some pixels are not fully charged, resulting in uneven brightness and lower contrast of the liquid crystal display, thereby the quality of the image displayed on the liquid crystal display is seriously affected.